Coupled multielectrode array sensors (see U.S. Pat. No. 6,683,463, U.S. Pat. No. 6,132,593, and U.S. Pat. No. 7,180,309) have been used for corrosion monitoring and electrochemical studies (see L. Yang and N. Sridhar, “Coupled Multielectrode Online Corrosion Sensor,” Materials Performance, 2003, September issue, page 48). The present invention is related to how to obtain a bounding localized corrosion rate using coupled multielectrode sensors, how to identify bad electrodes in a coupled multielectrode sensor, and how to eliminate the effects of such bad electrodes on the measurements of corrosion rates.